Grounding with a Earth box?

Someone with a grounding box:  What is the voltage differential measured between the grounding box and the "D" hole, the safety ground on a wall outlet?  Curious to see if a voltage can be seen between the grounding box and the earth ground of your home.

Basically same as Nordost for a fraction of the cost:

Puritan Audio Labs

^^^^Cost may very well be the ultimate determining factor for some but it’s worth pointing out, all artificial ground circuits do differ when it comes to details (impact) which may lead to us choosing one manufacturer over another. I highly recommend trying atleast 2-3 artificial grounding options before you settle with a brand that sounds the best in your system. 

I shown some photos to a cousin of my studying mineralogy at university of the so call special mixture of the Entreq.He said it look like Black Iron Oxide.Sells for $100 for a 20kg bag. .Entreq sells the cheapest unit for around $800US.I shown him the ads about magnetic balance with minerals contents and he laughed.

Hi all,

I have a friend that purchased an Entreq Poseidon and swears by it. He says it makes his system sound better. I have also been dabbling in making one of these for myself. Trying to find out what’s in them is like trying to get the recipe to Coca Cola! I did finish mine however and installed it on Saturday on my system. After about 20 minutes I was able to hear a bigger soundstage and much better imaging. It made my speakers disappear in my room.